1. Field of the Invention
This invention relates to an automatic exposure control device for a photographic camera wherein a setting to reflect the film speed of the film loaded in the camera is automatically made, and more particularly to a device for automatically controlling exposure in a photographic camera provided with a flash-matic means (explained hereinbelow) wherein a setting to reflect the film speed of the film loaded in the camera is automatically made in an exposure control means associated with the flash-matic means. More specifically, the exposure control device for a camera in accordance with the present invention automatically controls exposure with respect to two kinds of film speed, i.e. normal film speed and one special film speed, generally a high speed.
The flash-matic means mentioned above is an exposure control means for flash-light photographing provided in a camera including calculating means which takes into consideration the distance to the object to be photographed and illuminated by the flash light, the film speed of the film loaded in the camera and the guide number of the flash light.
2. Description of the Prior Art
It has been known in the art to take film speed into consideration in automatically controlling exposure in a photographic camera. In those cameras in which a film speed setting is automatically made in an exposure control means, code means indicative of the film speed is provided on a film magazine and is sensed by a film speed sensing means built in a camera.
This kind of camera provided with exposure control means is, on the other hand, disadvantageous in that the type of film usable therein is limited. In other words, these cameras cannot be used with normal conventional film magazines which do not have said code means indicative of the film speed. Therefore, in order to make it possible to use the camera with normal film, it has been suggested that a manual film speed setting means be provided on the camera.
However, the above mentioned camera provided with both automatic and manual film speed setting means suffers from the defect that the structure thereof becomes complicated and the manufacturing cost is raised.
Further, on the other hand, it has been known in the art to provide in a camera body a flash-matic means as defined above. The flash-matic device includes a calculating means which takes into consideration various factors necessary for controlling exposure when a picture is photographed with a flash light means, such as a strobo-flash light or a flash bulb. The calculating means is a mechanical structure employing cams and levers, and accordingly, it is very difficult to combine the flash-matic device with the normal exposure control means which usually employs an electric circuit. Therefore, there have been developed no cameras provided with a combination of a flash-matic device and an exposure control means capable of controlling exposure for various types of film of different film speed.
Under the above circumstances, it is common to provide a manual film speed setting means in cameras which use normal type of films, and to provide an automatic film speed setting means in cameras which use particularly designed films with film speed code means. Since there is only one widely used type of film, that is a negative color film having the film speed of ASA 100, there has been no problem in practice so far with these types of cameras only.
Recently, however, color films of negative type which have film speeds as high as ASA 400 have become commercially available. Thus, it is now desired that cameras should have a combination of an automatic exposure control means and a flashmatic means which is capable of controlling exposure for at least two types of film of different film speed both in daylight and in flash light.